Telephone system.



No. 824,980. PATENTED JULY 3, 1906. W. W. DEAN. TELEPHONE SYSTEM. APPLICATION FILED NOV. 9, 19os.

2 SHEETS-SHEET l.

No. 824,980. PATENTED JULY 3, 1906.

w. W. DEAN. TELEPHONE SYSTEM.

APPLICATION FILED NOV 9 1903 2 SHEETS SHEET 2 E Q E l l hlghl i l Hu- WILLIAM W. DEAN, OF CHICAGO,

ILLINOIS, ASSIGNOR TO KELLOGG SWITOHBOARD 'AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

I TELEPHONE SYSTEM.

, Specification of Letters Patent.

Patented July 3, 1906.

Inclination filed November 9,1903. SerialNo. 180,317.

To all whom it may concern.- Be it known that I, WILLIAM W. DEAN, a citizen of theUnited States of America, and a resident of Chicago, county of Cook, and

, State of Illinois, have lnvented a new and useful Improvement in Telephone Systems, ofwhich t e following is a specification.

My invention. relates to supervisory systems for telephone-lines, and has for its object generally to provide a system in which complete supervision in the most improved manner is carried out and in which at the same time the number of relays required for the operation of the supervisory system is reduced.

In the most lmproved supervisory systems .the signal-lamp is lighted whenever a connection is established and the subscribers telephone is upon its hook, but is extinguished during such connection when the subscribers telephone is off its hook. It must also be eX- tinguished under normal conditionsthat is,

when the connection is taken down from the subscribers line. 'VVith this arrangement of supervisory signals the operator is informed at all times of the. condition of each subscribers telephone.

It has been common heretofore in two-wire telephone systems, and particularly those systems in which the cord-circuits are provided with only two strands, to provide a pair of relays for each end of the cord-circuit, one being energized as long as the cord-circuit plug is connected with the and serving when so energized to cause the operation of the associated supervisory signal and the other relay being actuated only when the subscribers telephone is ofi its hook and serving when so energized to prevent the operation of the lamp. Thus under normal conditions and before the operator establishes a connection the supervisory signal is mert, since the first of said relays is unenergized; but when a connection is established and the said first relay is energized the lamp is lighted, but it is again extinguished when the said second relay is actuated by current over the telephone-line. In my invention I provide in connection with said two-strand cord-circuits a single relay for each end thereof, and the signal is associated with the correspondingend of the cord-circuit in such manner that it is lighted as soon as the connection telephone line is established, but is rendered inert when the subscriber responds. Thus with the one relay I am enabled to do the work of the pair of relays before mentioned and without the addition of extra strands to the cord-circuit. Wl1ile various arrangements are possible and which involve the principle of my invention, I prefer to arrange the said relay and su- I pervisory signal and a suitable retardation- J coil in series therewith in a bridge of each end of the cord-circuit. I then arrange the relay so that when de'energized the said signal is in circuit, but the retardation-coil is out of circuit but when the said relay is energized the reverse condition exists-that is, the lamp is cut out of circuit and the coil is cut into circuit.

My invention will be more particularly de' e accompanying scribed in connection with th drawings, which illustrate my invention, and i in which Figure 1 is a diagram showing the invention applied to one type of line-circuit, and Fig. 2 is a similar view showing the invention applied to a circuit of a different type.

eferring to Fig. 1, and L indicate subscribers lines extending in two limbs 2 and .3 from their respective substationsA and D to the central ofiice C, where the lines are fitted, as is usual, with a line-signal S and an answer ing-jack J and With a plurality of multiple acks J 2 and J in any desired number. The line-relay R is included in the extension 4 of I said line conductor 3 to the battery-lead 5, colmected with the live pole of the central common battery B, and serves to control the i local circuit of said line-signal S. The cut- 1 off relay R which is legged to ground from i the sleeve side of the jack-section of the line,

serves'when actuated. to disconnect the line conductor 3 from said conductor 4 and con- I nect it'with the sleeve side of the 'ack-section of the line and to disconnect the line conductor 2 from its normal ground connection and connect it with the tip side of said jack-section. At the substation each line is fitted with a common battery outfitof any desired or usual type, that shown including a si 1 mg-bell 6 and a condenser 7 in a bridge 0 the 1 line conductors normally closedat the switch- I hook 8, while a transmitter 9, receiver-10,, and' i through and the interposed condenserc,'while the nected with the tip si in circuit'by said switch-hook 8 when the receiver 10 is removed therefrom.

The operators connecting apparatus includes a number of cord-circuits, each of which is provided with an answering-plug. P- and a'calling-plug P having tip and sleeve contacts'adapted to register with the corresponding contact-surfaces of the spring-j acks of the line when inserted therein. The tipcontacts of said plugs are'eiectrically-united by the flexible'conductivestrands t and t conductor 2 and ground. l The current in this path actuates the line-relay R, which closes the local circuit of the line-signal S, which is lighted. to attract the attention of the operator. Upon seeing the signal. the operator inserts the answering-plug P of her cord-circuit .in the answeringqack J of the line, thereby completing a path forcurrentfrom the live pole of battery B through the lamp 5*, the shunt. of retardation-coil 12, which includes the conductors 13 and 14, the strand 8 of the cord-circuit, the sleeve side 0 the jack-section of. the line, and through the winding of the cut-off relay R to ground. The cut-off relay responds to current in this path and connects the external section of the line to the jack-section of the line, thus cuttingsoft the line-relay R and retiring the sig-' nal ers telephon'eis off its hook, current now flows over the metallic telephone-line and through the strand t of the cord-circuit and the supervisory relay T, which is energized to break the shunt about the retardation-coil 12 and to complete the short circuit about the supervisory lamp S which is accordingly'retired. Under these conditions the battery B is connected across the metallic talking-circuit with the relay 1 upon one side thereof' and the retardation-coil 12 upon the other. Having connected her head set with the cordcircuit now in use and learning the order of the calling subscriber, the operator proceeds to test the condition of the wanted line, which is sleeve-contacts thereofare. similarly joined by the strands s ands and the interposed condenser (3 Between the grounded pole of the battery B and the strand t is located the supervisory relay 1', and between the opposite pole oi the said battery and the strand 8 are placed the supervisor lamp S and the retardation-coil 12. U'n er normal conditionsthat is, when the said relay 1" is denergized-the retardation-coil 121-is shunted branch conductors 13 and 14 and the normal contacts of saidrelay';.bu t when the relayis energized said retardation-coil is cut into circuit and the lamp S is shunted through said conductor .13, the forward contacts of said relay, and the branch.conductor15. v

A second -batteryB is connected across the. calling end of the cord-circuit and has its live pole connected ,by a suitable conductor 16 with a certain number of the telephone-lines, i a second supervisory relay 1" being included between the other pole of the said source and the cord-circuit, while a supervisory signal'S is connected with a second retardation-coil 17 between the said live poleof said battery and the strand 3 of said circuit. Said relay 7* serves, as before, to normally control a shunt of the retardation-coil 17 through conductors 18 and 19 and the normal contacts of said relay, while when said relay is energized 'it closes a shunt of the supervisory signal S including conductor 18, the forwardcontacts of said relay, and the branch conductor 20.

The operators .set, including her head-receiver 21, the secondary of her induction-coil 22, and a suitable condenser 5 is adapted to be connected in a bridge of. the calling end of the cord-circuit through the medium of any suitable listening-key, fher transmitter. 23 and the primary of her induction-coil being charged from any suitable source of current, which may be either the battery B or B -A ringing-generator 2 1 is adapted to be cone of the line upon the depression of the springs of the ringing-key of the calling-plug to one of. the test-rings of the j ks of the said line. It will be observed that normally said test-rings are grounde through the cut-off relay, and since the tip of the plug-is likewise grounded through the supervisory relay 1 no flow of current takes place over the strand t when an idle line is tested. When a connection exists with the. line, however, the test-rings are connected with the live pole of either the battery B or l B through the sleeve-strand of the cord-circuit used for that connection, whereby the application of the grounded tip of the testinglug results in a flow'oi current over the testmgcircuit thus-completed and causes a surge of current through the operators bridge from said condenser c an ceiver tonotify-her that thelline is busy. Assumin that the line is found idle, the ca 1- vices and back to. the central ofiice over line Owing to the fact that the subscrib- I done in the usual manner by touching the tip a click in her re- 7 25, the sleev -strand' at the same time being ing-plu z is inserted in one of the multiple donnectedthrough the auxiliary conductor jacks o the line .a'ndthe ringing-key 25is. de- 26, including a suitable resistance 27,.with pressed. The initial insertion of the plug 1 the said conductor .16.. completes a path for current over thesleeve- In the operation of the system thus far described the subscriber- A, for example, takes up his receiverand thereby completes a path B arid through the cut-0E relay R which is energized to prevent the operation of the linestrand of the cord-circuit from. said battery signal of said line.

During ringing the path for current from the battery B is preferably auxiliary conductor 26, including the resistance 27, although it is side of the telephone-line, through the bell at l the substation, thence back to the central oflice, and through said conductors 26 and 16 and the battery B to ground. After the subscriber has been called, but before his response-current is flowing of the battery. B, through the lamp S the l l g from the live pole l shunt of the retardation-coil 17, including I conductors 18 and 19, and thence over the strand .9 and through the cut-ofi relay of the called line, as stated, the current in this path is sufficient to light th e supervisory and conductor of the telephone-line and winding eing connected between the line conductor 2 and the battery-lead 5 by conduc- The cut-off relay R has its windings n the line conductor 3 between the line-relay R and the spring-jacks of the line, said relay being shunted by an ordinary noninductive resistance 33 in the usual manner. The line-signal S has its circuit completed from the battery-lead 5 by means of conductor 34 to the front contact of the line-relay R thence by the spring of said relay and conductor 35 with the normal contact of said cut-off relay R the armature of which is grounded. In the cord-circuit the supervisory relay r, the supervisory signal S and the retardation-coil 12 are included in a bridge of the answering end of the cord-circuit, while said bridge intermediate the relay lamp is joined by a conductor 36 with lamp S the resistance of the said supervisory the live pole of said central and common batrent and opens the shunt about the retardation-coil 17 and completes the shunt consisting of conductors 18 and 20 around the supervisory lamp S thereby retiring the same to indicate to the operator the fact of the called subscribers' response. The subscribers are now in conversation, during which time the batteries B and B are independently supplying current to the lines L and L respectively, for the operation of the transmitters. The supervisory lamps S and S are extinguished by reason of the shunts completed about them by the relays r and r At the termination of the conversation the return of the subscribers receivers to their hooks opens the line-circuits to steady currents from the said central batteries and deenergizes the supervisory relays r and r which restore the conditions before describednamely,"that the supervisory circuits with the cut-off relays, froinwliicli circuits the retardation-coils 12 are excluded. Upon observing these signals the operator takes down the connection and restores all parts to normal condition. The retardationcoils 12 and 17 are preferably of one thousand ohms resistance, while the supervisory relays may be of one hunderd ohms resistance.

In Fig. 2 the line-circuits are slightly 'difl erent' in type, two onlynamely, L and If being shown, and the substation arrangement being the same as in the former figure. In this instance the line-relays R are providecl with split windings 30 and 31, winding 30 being legged to ground fromthe sleeve lamps are included in'loeal condenser c tery B. As in the former instance, the retardation-coil is normally shunted by conductors 13 and 14 through the normal contacts of the supervisory relay r which shunt is adaptedjto be opened and another one es tablished about the supervisory signal S by said condutbr 13 and the conductor. 15. he same "arrangement exists in connection with the calling end of the cord-circuit, eX- 5 cept that to facilitate making the busy test the retardation-coil 17 of the prior figure is now replaced by'a retardation coil or relay 1,

which in addition to performing the function of the retardation-coilserves to control the I00 circuit of the test-relay r. The bridge containing these parts is joined b T conductor 37 with the live pole of the battery B The spring 38 of the relay 1* serves to normally open the tip-strand t of the cord-circuit and to com plete the forward portion thereof through a conductor 39, connected with the auxiliary spring 40-upon the listening-key 41. When the listening-key 41 isoperated, said spring 40 connects with the winding of the high r'e- 1 IO sistance and high impedance test-relay T The operators head-telephone 21 and the are now included in a bridge of the cord-circuit with the secondary winding of an induction-coil 42, that is pr'ovided'with II 5 a tertiary winding included in the conductor 43, which the conductor 1s connected at one end with 16 and is adapted to be grounded at its opposite endby the test-relay r". The same ringing outfit is provided as in the former instance. Now when the subscriber L takes up his telephone current from the battery B flows over 'conductors5, 32, and2, thence through the substation defvices and back to the cent'ral'office through 12 5 line conductor 3, and tlnough the winding 30 of the line-relay R The current thus flowing through both windings of the line-relay-R actuates the same to close the local circuit of the line-signal S. The insertion of 1 0 and through the winding rent. and o ens the answering-plug P in response to the linesignal completes a pathfor current from the battery'B over conductor 36, through lamp vS, conductors 13' and 14', the sleeve-strand s signal S, w 'ch is retired. At the same time and owingto the fact that the subscriber has his. telephone off the hook the supervisory relay 1' receives suflicient current over thetip side-ofthe cord-circuit to open the short cir+ cuit about the retardation-coil 12 and close it about the lamp S vented r'romv operating. In testing the condition of the wanted line the test-relay is connected with the tip-contact of the plug 1? usual manner.

phone-line,

- complete the tip-strand t through the medium of the normal contacts of the relay r and the spring When it is line is idle, the calling-plug is inserted and the ringing-key depressed. The insertion of the calling-plug completes a path for current from the live pole of the battery B over con ductor 37', through the supervisory lamp S conductors 18 and ,19, and through the portion 45 of the winding of the impedance-coil or relay r thesleeve-strand. s of the cordcir'cuit,'-the sleeve conductor 3 of the teleincluding the winding of the cut ofl relay R, and through the winding 3001? the line-relay It? to ground. The cut-ofi relay is thus actuated to prevent the line-signal operating, and the depression'of the ringingkey'maintains the said cut-off relay, actu ated by current over'the conductors 16 and 26. After the subscriber has been calledand before his response the current flowing in the to light the superpath just traced serves visory lamp S attract its armature to disconnect the conductor 39 leading to the test-relay and to forconversation. Upon the response ofthe called subscriber the supervisory relay r receives suflicient current from the battery Bf flowing over the metallic telephone-line to actuate the same, the short circuit about the main portion 46 of the winding of the relay '1 thereby severing and completing the short circuit about the isfactorily,

both coils is preferably of one thousand ohms,

nected with the other end lamp S said short circuit including the condu'ctors 18 and 20. This retires the signal S and connects the impedance-coil or relay r in the bridge of the calling end of the cordcircuit. The resistance of the winding 45 may vary between rather .wide limits and may be as low as ten ohms and still work satwhile the combined resistances of the same as the retardation-coils 12, conof the cord-circuit.

which is thereby pre- 40 of the listen ing-key, the test being carried out in the found that the 'therefrom and when ener and to energize the relay 1' through the winding 45, thuscausing it to During conversation the batteries B and B are feeding current out to the lines L and L and'the supervisory relays and retardationcoils are connected in bridges of the cord-circuits.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is I 1. In a telephone system, With a telephone-line, of a cord-circuit to establish connections therewith for conversation; a supervisory-relay,

bridge of said cord-circuit; current, the said relay being in the. path 'of current fromsaid source overthe telephoneline durin conversation, and a local circuit establishe' with a portion of the line when connection is made therewith, said relay serving when denergized to include said lamp in said local circuit. and toexclude said vcoil ized toestablish the reverse conditions, su scribed.

' 2. In a telephone system,

tablishconnections therewith for conversation; a supervisory relay, a supervisory signal-lamp and a'retardation-coil in series in a bridge of. said cord-circuit; said relay being in the path of current to one side of the cordcircuit and over the telephone-line and therefore controlled by-the subscriber after a con-- nection is established, saidlamp andretarda-V- tion-coil'bein connected between the source of current an the otherside of the cord-circuit, saidrelay controlling shunt-circuits of said lamp and coil whereby when the relay is a su ervisory s1g-' nal-lamp and a retardatlon-coi in series 111 a a central source of 1 p the combination with a telephone-line, of a cord-circuit to esthe-combination stantially asde- Ioo deenergized the retardation-coil is shunted Y and the lamp is in circu't and when energized the lamp is shunted and the retardation-coil is in circuit, substantially as described;

3. In a telephone system, the combination with'a plurality of telephone-lines, circuit to establish connections. therewith for conversation, a condenser in each limb of. said cord-circuit to eonductively separate its two ends, a supervisory relay for each end of said cord-circuit with its coil in the path of current completed over the subscribersline when the cord-circuit is .connected therewith and ,the subscribers receiver is otl' hisv hook, a supervisory signal and a retardation-coilas sociated with the cord-circuit andnieans controlled by the actuation of said relay whereby either said si nal or said coil may be included in a path or current com leted bythe connection of its end ofthe c'or -circuit with a telephone-line, substantially as described. I

4 In a telephone s stem, the combination with a plurality of to ephone-lines, of a cord-- circuit adapted to establish "connections therewith for conversation, of a retardationcoil and a supervisory signal associated with said cord-circuit, a path of current completed ofa cordby the connection of said cord-circuit with a l Signed by me at Chicago, county of Cook, line, and means to include said si nal in and and State of Illinois, this 5th day of N ovein- IO exclude said coil from said pat before a ber, 1903.

called subscriber has responded to his call and to includesaid coil in and exclude said WILLIAM DEAN" signal from said path after the called sub- Witnesses:

scriber has answered his call, substantially as GAZELLE BEDER,'

described. ROBERT LEWIS AMEs. 

